0000000000263002
AUTHOR
J.j. Hunter
Grapevine row orientation mediated temporal and cumulative microclimatic effects on grape berry temperature and composition
Abstract Ambient radiation and temperature are global drivers of grapevine growth, grape yield and composition, and wine quality. Knowledge of the implications of vineyard row orientation/microclimate is required for decision-making in current and future macro- and mesoclimates. Temporal and cumulative microclimatic changes, induced by vine row orientation (NS; EW; NE-SW; NW-SE) of vertically trellised Shiraz grapevines, on berry pulp temperature and composition at different ripeness levels were investigated. Berries dynamically gained heat energy relative to: ambient climate/weather; direct canopy wall/bunch irradiance; and berry skin colour development. Berries exposed to direct solar rad…
Shoot Development and Non-Destructive Determination of Grapevine (Vitis vinifera L.) Leaf Area
A non-destructive method for determination of grapevine total leaf area is described. It is based on a highly significant correlation found between shoot leaf area and shoot length of Syrah (Vitis vinifera L.). Total leaf area per vine may be determined by using the equations described, by choosing a representative number of primary and secondary shoots and by knowing the total number of shoots of the plant considered. The equation seemed independent of vigour and terroir and reasonably sensitive to changes in leaf area that occurred independent of altered shoot length. It also allowed for recognition of compensation as a result of canopy manipulation. It would therefore be particularly use…
EFFECT OF TIPPING AND TOPPING ON SHOOT UNIFORMITY: PRELIMINARY RESULTS ON SINGLE CORDON TRAINED CABERNET SAUVIGNON AND MERLOT
The study was carried out in a two year old Merlot/140 Ru and Cabernet Sauvignon/140 Ru vineyards during the 2004 growth season. Vines were spaced 2.4 m x 0.9 m in North-South orientated rows. Each vine had five to six shoots. The vineyards were drip irrigated (800 m3/Ha/season). Shoots more than 100 cm were tipped or topped at pea berry size development stage. Tipping of Merlot vines reduced shoot growth and variability of all vegetative parameters. Topping of Cabernet Sauvignon reduced variability of shoot Diameter and increased lateral shoot growth.
Berry Size and Qualitative Characteristics of Vitis vinifera L. cv. Syrah
The effect of variation in berry size on berry composition was studied in irrigated Syrah/R99 grapevines, located in a temperate area of South Africa. Berries from 45 clusters, sampled from both sides of the canopy (east and west), were weighed to create four categories: 1. less or equal to 1.5 g; 2. between 1.51 g and 2.00 g; 3. between 2.01 g and 2.50 g; 4. more than 2.50 g. Berry physical characteristics were determined and total anthocyanins and seed flavonoids were analysed by spectrophotometry and anthocyanin profiles by HPLC. The ratio of skin weight:berry weight did not change with increasing berry size, but the ratio of seed weight:berry weight increased. For total anthocyanins, va…
Berry characterisation of cv shiraz according to position on the rachis
In this study, characterisation of the physical and compositional parameters of berries located in different positions on the rachis of Shiraz/R99 bunches was done. Berries were divided according to position on the rachis (apical, median and basal) and berry weight, resulting in four berry weight classes, averaging 0.86 g, 1.29 g, 1.74 g and 2.26 g and 0.74, 1.18, 1.59 and 2.09 cm3, respectively. The berries were analysed individually. The fresh weight of the berries comprised approximately 4% seeds, 20% skin and 76% flesh. Different percentage distributions were found for each class of berry weight and according to position on the rachis. From the top to the bottom rachis position, an incr…
Integrative effects of vine water relations and grape ripeness level of vitis vinifera L. cv. Shiraz/Richter 99. II. grape composition and wine quality
Regulation of grapevine water status is a common practice to manipulate grape composition and wine quality. In this investigation the effect of plant water status (two field water capacity-based irrigation levels, 75% and 100%, applied at single and combined vine developmental stages) and ripeness level (harvesting at different soluble solid levels) on grape composition and wine quality of Vitis vinifera L. cv. Shiraz/ Richter 99 was determined. Integrative effects of vine water relations and grape ripeness level, specifically in a Mediterranean high winter rainfall area, have not yet been investigated systematically. Source:sink mechanisms and dynamics and compositional and physical change…